1. Field of the Invention
The present invention relates to a capo for a stringed instrument, in particular a guitar, banjo or similar such instrument.
2. Background Art
A capo, sometimes variously termed a capodastro, capodaster, capo tasto or cejilla, is a device well-known and used by players of stringed instruments and in particular guitar and banjo players. A capo can be used with a stringed instrument, for example a guitar or banjo, which has a neck and a set of strings extending along the length of the neck. The neck comprises a fingerboard portion adjacent to the strings and a back. The fingerboard includes a number of fret bars which protrude slightly from the fingerboard/neck surface and extend laterally across the neck. The capo, when applied, serves to hold the strings against the fingerboard provided along the neck, and in particular against one of the number of fret bars disposed along the length of the fingerboard and which extend from the fingerboard, to reduce the effective length of the strings and therefore adjust the pitch produced by the strings.
When a capo is in use on an instrument neck a string-engaging portion or arm of the capo is arranged to press the strings against the surface of the fingerboard to sandwich the strings against the fret bars and/or fingerboard. In order to press the string-engaging portion against the fingerboard the capo is required, and includes suitable means for it, to be clamped to the neck. In a number of previous capo designs the clamping of the capo to the neck has been provided through the use of relatively cumbersome clamping mechanisms utilizing screw mechanisms, toggle levers, springs and other means which are difficult to handle and/or time consuming to attach. In particular, the constructions of previous capos have generally been such that the acts of attaching one to an instrument neck, removing it, or moving its position have undesirably required the use of two hands.
There are numerous examples of such capo designs including such clamping mechanisms. In particular examples of such designs are proposed and described in the following patents: U.S. Pat. No. 5,492,045; U.S. Pat. No. 4,149,443; U.S. Pat. No. 6,965,067, US 2004/0261600, U.S. Pat. No. 390,612 and U.S. Pat. No. 5,792,969.
In other prior capo designs spring activated mechanisms (generally torsion springs) are used to provide the clamping force. Examples of such capos are described in U.S. Pat. No. 4,143,576, U.S. Pat. No. 6,528,711, U.S. Pat. No. 4,583,440, U.S. Pat. No. 5,623,110, US 2005/0098019 and U.S. Des Pat. 378,825 and U.S. Des Pat. 372,259. With the spring type capo designs the string-engaging arm is pivotally attached at one end to a clamping arm. In use the capo is fitted to the instrument neck with the string-engaging arm abutting against the strings and pressing the strings toward the fingerboard whilst the clamping arm abuts and bears against the opposite rear surface of the neck. A torsion spring is provided within/adjacent to the pivotal mounting to urge the two arms together, with the strings and neck of the instrument sandwiched therebetween, and provide the clamping force.
As described in the prior patents such spring type capo designs are easier and quicker to apply and can be fitted by the player one handed. However, the force generally required to be applied by the user to apply, adjust or remove such spring activated capos is high and uncomfortablef or the user.
A further prior capo design described in U.S. Pat. No. 6,008,441 has sought to alleviate this problem by use of a toggle type linkage. This linkage, however, adds to the bulk and cost of the device.